Encapsulated electrophoretic displays having a monolayer of capsules and materials and methods for making the same

• US 7,242,513 B2
• Filed: 05/20/2004
• Issued: 07/10/2007
• Est. Priority Date: 08/28/1997
• Status: Expired due to Fees

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink Holdings Incorporated
• Inventors: Albert, Jonathan D., Steiner, Michael L., Comiskey, Barrett, Amundson, Karl R., Drzaic, Paul, Loxley, Andrew, Crossley, Glen, Geramita, Katharine, Valianatos, Peter J.
• Primary Examiner(s): Sugarman; Scott J.
• Assistant Examiner(s): Pinkney; DaWayne A.
• Application Number:
  US10/851,706
• Publication Number:
  US 20040217929A1
• Time in Patent Office: 1,146 Days
• Field of Search: 359295-296, 345/107
• US Class Current: 359/296
• CPC Class Codes: B41J 3/4076 printing on rewritable, bistable "electronic paper" by a focused electric or magnetic field
• CPC Class Codes: G02B 26/026 based on the rotation of particles under the influence of an external field, e.g. gyricons, twisting ball displays based on orientable dipolar particles G02F1/172; based on electrophoresis G02F1/167
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/133348 Charged particles addressed liquid crystal cells, e.g. controlled by an electron beam
• CPC Class Codes: G02F 1/13336 Combining plural substrates to produce large-area displays, e.g. tiled displays
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/1343 Electrodes reflective electrodes G02F1/133553
• CPC Class Codes: G02F 1/1345 Conductors connecting electrodes to cell terminals
• CPC Class Codes: G02F 1/135 Liquid crystal cells structurally associated with a photoconducting or a ferro-electric layer, the properties of which can be optically or electrically varied G02F1/133348 takes precedence
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/16757 Microcapsules
• CPC Class Codes: G02F 2202/12 photoconductor
• CPC Class Codes: G02F 2202/28 Adhesive materials or arrangements
• CPC Class Codes: G06F 3/1446 display composed of modules, e.g. video walls
• CPC Class Codes: G06F 3/147 using display panels
• CPC Class Codes: G06K 19/07703 the interface being visual
• CPC Class Codes: G09F 9/302 characterised by the form or geometrical disposition of the individual elements
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field
• CPC Class Codes: G09G 2380/04 Electronic labels
• CPC Class Codes: H10K 10/462 Insulated gate field-effect transistors [IGFETs]
• CPC Class Codes: H10K 19/00 : Integrated devices, or assemblies of multiple devices, comprising at least one organic element specially adapted for rectifying, amplifying, oscillating or switching, covered by group H10K10/00
• CPC Class Codes: H10K 85/30 : Coordination compounds
• CPC Class Codes: H10K 85/60 : Organic compounds having low molecular weight H10K85/10 - H10K85/50 take precedence

Abstract

An encapsulated electrophoretic display having a plurality of non-spherical capsules disposed substantially in a single layer on a substrate.

Claims

1. A process for creating an encapsulated electrophoretic element having a plurality of capsules disposed on a substrate in substantially a single layer, the process comprising the steps of:

(a) providing the capsules;

(b) mixing capsules with a binder to create a capsule/binder mixture;

(c) coating the capsule/binder mixture onto an at least partially conductive substrate, thereby to create a film comprising the capsules in substantially a single layer; and

(d) curing the capsule/binder mixture.

2. The process of claim 1 wherein the binder is selected from the group consisting of acrylic, urethane, and poly(vinyl alcohol).

3. The process of claim 1 wherein the binder comprises a polymer latex.

4. The process of claim 1 wherein a fraction of the binder is capable of evaporating and the step of curing the mixture comprises evaporating the fraction of the binder.

5. The process of claim 1 wherein the substrate comprises an indium tin oxide sputtered polyester film.

6. The process of claim 1 wherein at least one of the capsules contains a plurality of particles dispersed in a suspending fluid.

7. The process of claim 1 wherein the coating step comprises applying pressurized gas to the capsule/binder mixture, thereby to cause deposition of the capsule/binder mixture onto the substrate such that the capsules are disposed on the substrate in substantially a single layer.

8. The process of claim 7 further comprising heating the pressurized gas to a temperature higher than an ambient temperature prior to applying the pressurized gas to the capsule/binder mixture.

9. The process of claim 7 further comprising cooling the pressurized gas to a temperature lower than an ambient temperature prior to applying the pressurized gas to the capsule/binder mixture.

10. The process of claim 7 further comprising adding a liquid to the pressurized gas.

11. The process of claim 10 wherein the liquid comprises at least one droplet.

12. The process of claim 10 wherein the liquid comprises an organic solvent.

13. The process of claim 12 wherein the organic solvent comprises an alcohol.

14. The process of claim 7 wherein the coating step comprises applying the pressurized gas with an air knife.

15. The process of claim 7 wherein the pressurized gas is applied from a distance of about 1 cm to about 15 cm from the surface of the capsule/binder mixture.

16. The process of claim 7 wherein the pressurized gas is applied at an angle of from 0 degrees to 90 degrees from the surface of the conductive substrate.

17. The process of claim 1 wherein the coating step comprises coating at least some of the capsules onto the substrate through a coating head comprising a slot die coating head.

18. The process of claim 17 wherein a width of a slot of the slot die coating head is between about 1 and about 2.5 times the mean diameter of the capsules.

19. The process of claim 1 further comprising laminating the film with a rear substrate.

20. The process of claim 19 wherein a layer of material is disposed between the film and the rear substrate.

21. The process of claim 20 wherein the layer of material is associated with the rear substrate prior to laminating.

22. The process of claim 20 wherein the layer of material is associated with the film prior to laminating.

23. The process of claim 19 wherein heating occurs during the step of laminating.

24. The process of claim 19 wherein pressurizing occurs during the step of laminating.

25. The process of claim 19 wherein evacuating of a gas occurs during the step of laminating.

26. The process of claim 20 wherein the layer of material comprises an insulator.

27. The process of claim 20 wherein the layer of material comprises a conductor.

28. The process of claim 20 wherein the layer of material comprises a semiconductor.

29. The process of claim 20 wherein the layer of material is in a liquid state during at least a portion of the laminating step.

30. The process of claim 20 wherein the layer of material comprises the binder.

31. The process of claim 20 wherein the step of laminating produces a stratum comprising the capsules, the binder, and the layer of material and having at least one substantially planar side proximate the rear substrate.

32. The process of claim 20 wherein the step of laminating produces a stratum comprising the capsules, the binder, and the layer of material, the stratum being substantially free from voids.

33. The process of claim 20 wherein the layer of material has a thickness of less than or equal to about 50 μ

m.